package chapter10;
import javax.swing.plaf.nimbus.State;
import java.sql. *;
public class Example01 {
    public static void main(String[] args)throws SQLException{
        /*
        * JDBC连接数据库
        * 1.加载 驱动
        * 2.连接
        * 3.表结构-预处理(sql)
        * 4.执行SQL语句
        * 5.结果
        * 6.释放 连接
        /*
        * (1)加载
        * a.根据目录创建lib文件
        * b.将连接的java包放入lib
        * c.点击 文件->项目结构->模块->依赖->+号->JAR或目录->选中mysql的jar包
        * d.编写加载代码
        * */
        Statement stmt = null;
        ResultSet rs = null;
        Connection conn = null;
        try{
            //1.注册数据库的驱动
            Class.forName("com.mysql.cj.jdbc.Driver");
            //2.通过DriverManager获取数据库
            String url ="jdbc:mysql://localhost:3306/jdbc?serverTimezone=GMT%2b8&useSSL=false";
            String username = "root";//数据库账户
            String password = "0324love502";
            conn = DriverManager.getConnection(url,username,password);
            //3.通过Connection对象获取Statement对象
            stmt = conn.createStatement();
            //4.通过Statement执行SQL语句
            String sql = "select * from users";
            rs = stmt.executeQuery(sql);
            //5.操作ResultSet结果集
            System.out.println("id | name | password "+"|email | birthday");
            while (rs.next()){
                //每轮训练 rs代表一行数据
                int id = rs.getInt("id");//通过列名获取指定字段的值
                String name = rs.getString("name");
                String psw = rs.getString("password");
                String email = rs.getString("email");
                Date birthday = rs.getDate("birthday");
                System.out.println(id+"|"+name+"|"+psw+"|"+email+"|"+birthday);
            }
        }catch (ClassNotFoundException e){
            e.printStackTrace();
        }finally{
            //6.回收数据资源
            if (rs !=null){
                try{
                    rs.close();
                }catch(SQLException e){
                    e.printStackTrace();
                }
                rs = null;
            }
            if (stmt != null){
                try{
                    stmt.close();
                }catch (SQLException e){
                    e.printStackTrace();
                }
            }stmt =null;
        }
            if(conn !=null){
                try{
                   conn.close();
            }catch (SQLException e){
                   e.printStackTrace();
            }conn = null;
        }
      }
     }